Millions of adults are taking aspirin daily without their doctor's advice or knowledge, probably increasing their risk of major bleeding, suggests an analysis based on a national cohort in the United States. Its findings suggest that nearly one-quarter of adults 40 years and older without cardiovascular (CV) disease, 23.4% in the survey study, may be taking aspirin daily for primary prevention. Nationally, that's about 29 million people, the researchers note. Of that group, 23% were taking aspirin without a physician's recommendation, corresponding to about 6.6 million adults, the report says. Nearly half of people at least 70 years of age in the survey, 44.6%, were on aspirin for primary CV prevention. Having a history of peptic ulcer disease did not seem to deter people from taking aspirin regularly; it wasn't a predictor of lower aspirin use. "This is a big problem," senior author Christina Wee, MD, PhD, Beth Israel Deaconess Medical Center, Boston, told theheart.org | Medscape Cardiology. But it's not necessarily surprising, she said, "because a lot of people get their health information from their family, friends, the internet. And even doctors, until fairly recently, were not discouraging aspirin use and may have been on the fence about it." The findings are based on data from the 2017 National Health Interview Survey (NHIS) from 14,328 adults (mean age, 57.5 years; 54% women, 33% nonwhite). The analysis was published July 22 in Annals of Internal Medicine, with lead author Colin W. O'Brien, MD, Harvard Medical School, Boston. The survey queried whether the respondents were on "low-dose" aspirin without defining that that meant. "My question is whether all the people taking aspirin are really informed about what we know regarding risks and benefits," noted outcomes researcher Harlan Krumholz, MD, Yale School of Medicine, New Haven, Connecticut, told theheart.org | Medscape Cardiology. "We need to make it easy for people to make the best choices for themselves. It is likely that many of these people, if properly informed, would choose otherwise," added Krumholz, who is not a study coauthor. Last year, as the report notes, results from three major primary prevention trials shifted the balance between perceptions of the CV benefit from aspirin therapy and the associated bleeding risk. The trials' results were unveiled after collection of the NHIS data. The benefit of aspirin on risk for serious vascular events in the ASCEND trial did not outweigh the increased risk for serious bleeding in patients with diabetes, as previously reported. In the ARRIVE trial, there was no difference in CV or cerebrovascular events between nondiabetic patients with other CV risk factors but no history of events who were taking preventive aspirin and those who were not. The ASPREE trial showed increased all-cause mortality and unchanged CV mortality in people in the community 70 years and older assigned to take aspirin. In large part because of the three trials, the American Heart Association and the American College of Cardiology (AHA/ACC) issued updated aspirin recommendations in March. They advise against routine aspirin use in people older than 70 years and those with increased bleeding risk. Routine aspirin may be considered in adults 40 to 70 years of age at high risk for CV disease with no increased bleeding risk, they state. "People may think that because it's over the counter and it's been called 'the wonder drug' for 30 years it must be pretty safe," Susan Smyth, MD, PhD, told theheart.org | Medscape Cardiology. "Now we have to work to get the word out to talk to your doctor first before starting aspirin," said Smyth, Gill Heart and Vascular Institute, University of Kentucky, Lexington, who is not associated with the current analysis. "As physicians, we are reasonably good at implementing guideline-directed medical therapy when we know something works. What we don't do a very good job at is de-implementing when we learn that it maybe doesn't work so well. De-implementation is much harder," she said. However, she said, it's equally important to remember that for patients at high risk and those with known coronary disease, aspirin remains a key component of lowering the risk of having a first or second heart attack or stroke. Wee reports no relevant conflicts; disclosures for the other authors are in the report. Smyth had no relevant disclosures. Krumholz reports personal fees from UnitedHealth, IBM Watson Health, Element Science, Aetna, Facebook, Arnold & Porter, and the Ben C Martin Law Firm; grants from the Centers for Medicare & Medicaid Services, Medtronic, Johnson & Johnson, and the US Food and Drug Administration; and serving as founder of the personal health information platform Hugo. Ann Intern Med. Published online July 22, 2019. Abstract Source